Spark-coil.



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il umm M Wnun 1 www gica BUTLER AMES, OF LOWELL, MASSACHUSETTS.

SPARK-COIL.

Specicationof Letters Patent.

Patented Sept. 7, 1915.

Application filed March 28, 1914. Serial No. 827,871.

7 10 all whom t may concern Be it known that l, BUTLER AMns, a citivzen of the United States, residing at Lowell, Vin the'county of Middlesex and State of Massachusetts,v have invented certain new and useful Improvements in Spark-Coils, of which the following is a specification, reference beinghad therein to the accompanying drawings. L

The principal object of my invention is to avoid the objectionable noise dueto the impact of the'two resilient leaves of a compound vibrator having a fixed amplitude between them; and I attain it by mounting one or more leaves betweenthe Atwo leaves already in use 'so that, with the same amplitude between the top and bottom leaves, any two adjacent leaves are normally nearer each other than formerly; consequently, as all the leaves do not act simultaneously, each moves through less space, and with less momentum, and there is less strength of impact between the contacting leaves, and hence, less noise.

A further advantage of my vibrator over prior compound vibrators having only two leaves, lies in the fact that with substantially the same flexibility, it has in its two or more lower leaves more metal than is contained in the ordinary single lower leaf, while, it is thought, also, that the air between the lower leaves, serves as a sufcient Vmagnetic insulation to delay the successive magnetization of the leaves, and permit the magnet a longer time to build up before the primary circuit is broken; all with the result that the lower leaves acting through the connecting pin, strike the top leaf of the vibrator with greater momentum to break the primary circuit; and the vibrator can be successfully used when the gasolene engine operating the magneto, is running at a com paratively low speed.

Another feature resides in means whereby the exposed primary circuit of a spark coil mounted in a grounded metallic case, is

less likely to become short circuited. It also avoids annoying shocks resulting from inadvertence in handling the coil; as by manually touching the exposed primary circuit and the metallic containing case.

In the drawings illustrating the principle nf my invention, andthe best mode now known to me of embodying the same in operative structure, Figure 1 shows my invention, in elevation, the case and cover being partly in section; Fig. 2 is a plan thereof;

Fig. 3 is an enlarged plan of one feature of my invention; Fig. 4 illustrates, in side elevation, what is shown in Fig. 3 Fig. 5 is an enlarged longitudinal section on line 5%5 in Fig. 3. i

A inetal case A has therein a spark coil box B with vibrating mechanism mounted over a core B', in dotted lines, and upon a piece of suitableinsulation C forming the top portion of the box. vibrator D has three metal leaves l, 2, 3, secured together at their rear end portions by hollow rivets E; there being also a further rearwardly and upwardly extendingbifurcated member F of the top leaf l whereby, as will later appear, the desired spring tension may be imparted to the vibrator. Through the middle of these leaves, extends a stud G, its lower part being rigidly secured in the bottom plate 3, while its other end portion freely passes through the two other leaves l, Q, and is provided with a head H, the under side of which is properly distant from the topside of the bottom leaf 3 to allowthe required amounts of motion between the leaves. The free end portion of the top plate 1 is provided with a suitable contact I', as of platinum, to engage a similar contact J, in the bridge K. This vibrator is secured in operative position upon the top insulation C, in the usual manner, by means of two screws L passing through suitable holes M in ears N formed in the rear portions of the .two lower leaves 2. 3, of the vibrator, these screws serving also to connect the vibrator in the primary circuit, in a well known way. The rearwardly extending adjusting spring' F is operatively connected to a collared screw connection O, embraced by the bifurcations P, P, of the spring, and threaded to the pin Q fast in the top insulation. Rigidly secured on top of the collar is a finger head R of insulation, the movement of which may be frictionally controlled, as by a spring niember S, secured to the insulation and` engaging the under side of the finger head.

Without further explanation, it will be seen, first: that the collared screw connec-l tion O upon which the finger head R is mounted, and which is part of the primary circuit.y is sufficiently distant from the grounded metallic case A to prevent a short circuiting of the primary current; while at the same time, theinsulated head so protects the users hands from accidentally 'contactd ing both the metallic case, when the cover T is removed, and the metal parts of the vibrator, that it is practically impossible for the user of the coil to receive disagreeable shocks from the electrical current. Second: that by mounting one or more leaves, as 2, between the top and bottom leaves 1, 3, any two adjacent leaves are normally nearer each other than formerly; consequently, as all the leaves do not act simultaneously, eachmoves through less space, and with less momentum, and there is less strengthof impact between the contacting leaves, and hence, less noise. Third: that my vibrator, when compared with prior compound vibrators, has substantially the same flexibility, and yet, in its two or more lower leaves 2, 3, has more metal than is contained in the ordinary single lower leaf; while, it is thought, also, that the air between the lower leaves, serves as a magnetic insulation to delay the successive magnetization of the leaves, and permit the magnet a longer time to build up before the primary circuit is broken; all with the result that the lower leaves 2, 3, actin through the connecting stud G and head strike the top leaf l of the vibrator with greater momentum to break the primary circuit between the contact oints I, J; and the vibrator can be success ully used when the gasolene engine operating the magneto, is running at a comparatively low speed.

Having described my invention and the best mode of operation now known to me of embodying the same in operative structure,

and desiring to claim the same in the broadest manner legally possible, what I claim 1s:-

l. In a spark coil, a metallic vibrator having more than two resilient leaves secured together at one end; and means whereby the movements of each leaf are limited in `relation to each other.

2. In a spark coil, a metallic vibrator, having three resilient leaves secured together at one end; and a stud which is secured in an outside leaf, passes through the other two leaves, and has upon its free end portion a. head, whereby the movements of each leaf are limited in relation to each other.

3. In a spark coil, a bridge, a. metallic vibrator to engage said bridge and having three resilient leaves secured together at one end; a stud which is provided with a head, is secured to one outside leaf, passes through the middle leaf and the outer leaf which may engage the under side of the head; the top leaf being provided with a rearwardly extending adjusting spring; and means to give the vibrator the desired tension; all designed so as to limit the movements of each leaf in relation to each other, to avoid objectionable noise, and also permit a long make, and a quick break, by the vibrator.

In testimony whereof I hereunto affix my signature in the presence of two witnesses.

BUTLER AMES.

Witnesses:

JOHN MGKENNA, JOSEPH A. LEGARE.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

